Centrifugal clutch



March 13, 1934 J BETHENOD ET AL I Re. 19,110

CENTRIFUGAL CLUTCH Original Filed April 22, 1927 2 Sheets-Sheet l INVENTORS Jo sap/1 5 e fire/10d & Huyue; 6oa 'f ATTORNEY March 13, 1934.

J. BETHENOD ET AL CENTRIFUGAL CLUTCH Original Filed April 22, 1927 2 Sheets-Sheet 2 M f 3, mMu W80 56 I h a My a ATTORNEY UNITED STATES PATENT OFFICE CENTRIFUGAL CLUTCH Joseph Bethenod and Hugues Goudet, Paris, France, assignors to The Falk Corporation, Milwaukee, Wis., a corporation of Wisconsin Original No. 1,817,542, dated August 4, 1931, Serial No. 185,770, April 22, 1927. Application for reissue July 24, 1933, Serial No. 682,021. In France May 10, 1926 6 Claims. (Cl. 192-105) Our invention relates to centrifugally con- 33 of Fig. 2, some of the partsbeing broken trolled means for coupling motors and the loads away. to be driven by them and, more particularly, to Referring first to Fig. 1, shaft 1 of the motor centrifugally actuated clutches for coupling in- (not shown) has a circular plate 2 rigidly fastened l duction electric motors and machine tools or other to it which carries a plurality of levers 3, pivoted 60 load devices to be driven thereby. to it at 4. The levers 3 have shoes 5 at their free Clutches embodying means for utilizing cenends that are biased toward the axis of rotation trifugal force have heretofore been employed in by means of springs 6. starting machine tools driven by squirrel-cage in- A pulley 7, which is operatively connected to duction motors, it being well known that a motor the machine tool or other load device, has a hub 8 5 of the type just mentioned has a relatively low C-unt d loo y up S a t The W 9 0 t e starting torque and that the use of a clutch emp y 7 s a groove 10 to b engaged y the bodying means for utilizing centrifugal force pershoes 5. A plurality of levers 11 are pivoted to mits starting the motor under reduced load. the web 9 at 12 and are biased toward the axis of 1| A close study of the problem shows, however, ot y Springs The free ends 0f the 70, that a centrifugal clutch can give satisfactory levers 11 are provided With Shoes 14 engage 5 results only by adding certain elements, it being groove 15 in plate 2. essential that the clutch shall permit the motor The operation of the apparatus is as follows: to carry a momentary overload without Slipping, As the speed of rotation of shaft 1 increases, the

It has been proposed, therefore, to employ a centrifugal force impels the shoes 5 against the 7 lubricant to partially neutralize the action of the walls of the groove 10, thus progressively exertclutch during the first moment of starting. Being a torque upon the pulley '7, the maximum of cause of the use of a lubricant, the torque applied which can be determined by suitably designing to the motor during the starting may be mainthe various cooperating elements; this torque tained below the maximum torque which the ay be es o p 110 be equal to 1Jhe so. clutch can withstand without slipping, once the no mal t qu o t 111011012 Consequently. t supply of lubricant between the engaging surpulley 7 begins to turn at a rate of acceleration faces is dispersed under the action of the cenw ch d pe ds on t inertia 0f t revolving trifugal force. parts of the driven machine. As soon as the 80 The presence of a lubricant necessitates a cerpe increases fi y, Shees u h tain care of the apparatus, and the surrounding the action of centrifugal force, engage the walls temperature may eventually influence the operaf t e E OO 15 d Complete the p ess ve tion. clutching between the shaft 1 and the pulley 7.

Hence, such a solution would hardly permit the It will be understood that the simultaneous ac- 35 adjustment of the clutch to the different condi- 131011 of the Shoes 5 and 14,,Wheh the P y 7 is 90.

tions of use and could not be suitable when the eempletely clutched t0 the Shaft y be fiinertia of the revolving parts of the machine tool slant avoid any Slipping in e e motor caris considerab1e ries a certain overload.

Other solutions have been proposed, with the It is ungerstood that the maximum terque due 40 object of obtaining the desired retardation in the m the acbwn 0f Shoes 5 meyhe Selected difieror operation of a clutch, but they are all complicated E m the'normal torque In accordance With and delicate the considered application.

The object of the present invention is to proon the t hand it is quite evident that the vide a simple and strong construction which will 53;; I ig iifi exerflsed by Shoes ensure the starting of an electric motor of the p We 0 e angu ar Speed may no also be advantageous to ensure by any suitable induction type under the most favorable conditions for each application expedient, application of the shoes 14 only in case pulley '7 reaches a speed close to normal speed Our invention will be readily understood by It is understood that the em referring to Fig. 1 of the drawings, which is a bodlment shown in Fig. 1 is subject to a great many variations, a longitudinal, sectional View, somewhat schematic for i t ce, the number 01 lever 3 nd 11, m2 m5 in character, of gne embodiment thereof. shape of the grooves 10 and 15 and the character Pig. 2 1s a longitudinal, sectional view of a preof the springs 6 and 13, which, in fact, could be ferred embodiment of our invention, and omitted, if desired.

Fig. 3 is a transverse sectional view on line Figs. 2 and 3 show a preferred embodiment of n the invention, which is, in practice, a very strong apparatus and not expensive.

Shaft 1 has a key seated member 2 which is located inside the pulley 7 The pulley is mounted loosely upon the member 2, as indicated at 8, 8 and has a removable cover 18 which permits mounting it in position. The cover 18 is provided with radial wings 16 which are uniformly distributed and which carry with them independently movable parts 14 in their rotation, while allowing them a certain radial displacement.

Member 2 is also provided with wings 17 which carry independently movable parts 5 having the same shape as the parts 14 As soon as shaft 1 speeds up, the parts 5 are forced, by centrifugal action, against the interior surface 10 of the pulley 7, thus starting the operation, as before. As soon as a certain speed is reached, the friction of parts 14 against the interior surface 15 of the bell of the member 2 completes the clutch-action, as was explained in connection with what is shown in Fig. 1.

With this construction, all countersprings for parts 5 and 14 will generally be unnecessary, but the use of them remains a possibility. Then again, parts 5 and 14, or the corresponding parts 5 and 14, may be made of different weights by differences in shape or by employing materials of different densities, although the adoption of a single shapeand a single material will be more advantageous for manufacturing reasons. By changing the widths of the friction parts to conform to the axes of different pulleys, it is, of course, possible to modify the relation of the corresponding friction torques of the two clutches.

It is also to be noted that the parts in question, as shown in Figs. 2 and 3, are constituted by multiplying elementary parts of the same length, in accordance with the length of the pulley. Also, by making the multiple parts of different materials, it is possible to vary, within very great limits, the ratio of the friction torques exercised by surfaces 10 and 15. Besides, such a preferred arrangement of the invention offers a 1 considerable advantage, so far as the friction members themselves are concerned, for each elementary part acts independently under the action of the centrifugal force and one can thus dispose surely of a great number of friction points, even in case the finish of the rubbing parts is not quite perfect.

There is another important inconvenience which has been found with the clutches at present in use and which consists in the abnormal heating, resulting from the operation of the apparatus. To obviate efficiently this heating, openings 19, 20, 21, and 22 are provided as another important characteristic of the invention. Air enters through the openings 19 and'20 near shaft 1 and escapes through openings 21 and 22 situated near the periphery, after having cooled the various elements of the apparatus. The circulation of the air is materially increased by the disposition of parts 5 and 14 and the wings l6 and 17,

each unit constituting a real centrifugal ventilator.

Finally, it is to be noted that certain dispositions which are described herein, and particularly the division of the parts and the internal ventilation of the pulley may be very advantageously applied to simple clutches, that is to say, those having no double friction.

What we claim and desire to secure by Letters Patent of the United States is:

1. A centrifugal clutch for coupling a motor to its load comprising two sets of successively actuated members working in parallel, the action of one of which depends upon the speed of the driving motor and the action of the other of which depends upon the speed of the load driven by the said motor, the successively actuated members being composed of elements of like clutch-face contour.

2. A centrifugal clutch for coupling a motor to its load comprising two sets of successively acting members working in parallel, the action of one of which depends upon the speed of the driving motor and the action of the other of which depends upon the speed of the load driven by the said motor, each of the successively actuated members being composed of a plurality of elements of like contour and being both jointly and severally operative.

3. A centrifugal clutch for coupling an electric motor to its load comprising two successively acting sets of elements, the action of one of which depends upon the speed of the driving motor and is reinforced by the second set, the action of which depends upon the speed of the load driven by the said motor, each of the successively actuated sets being composed of like elements, rotation of which is effected by means of wings which ensure internal ventilation of the clutch.

4. In a centrifugal clutch mechanism the combination of driving and driven rotary members. two friction clutches arranged in parallel therebetween, one of said clutches comprising a plurality of centrifugally actuated friction shoes responsive to rotation of said driving member to effect a driving connection between said members, and the other of said clutches comprising a plurality of centrifugally actuated friction shoes responsive to rotation of said driven member to increase the torque transmitting capacity of said connection.

5. In a centrifugal clutch mechanism the combination of driving and driven rotary members, two independently operable friction clutches arranged in parallel therebetween, one of said friction clutches having centrifugally actuated means responsive to rotation of said driving member to effect a driving connection between said members, and the other of said friction clutches having centrifugally actuated means responsive to rotation of said driven member to increase the torque transmitting capacity of said connection.

6. In a centrifugal clutch mechanism the combination of driving and driven rotary members, and two automatic friction clutches arranged in parallel therebetween, one of said friction clutches providing an initial torque transmitting medium through which said driven member is actuated when said driving member is actuated, and the other of said friction clutches responding to rotation of said driven member to provide a second torque transmitting medium between said members.

JOSEPH BETHENOD. HUGUES GOUDET. 

